This invention relates to a bearing assembly. In particular, this invention is directed at a seal structure in a bearing assembly which minimizes the internal contamination of the bearing assembly.
Conventionally, bearings include an inner race and a separate outer race which is movable relative to the inner race. To provide fluid rotation of the inner and outer races relative to one another, most bearings aim to smooth and/or minimize the frictional resistance between the components of the bearing. Often, this is achieved by selecting the bearing surfaces of the races and any intermediate bearing elements to have desirable tribological features (i.e., to have low coefficients of friction). In some cases, lubrication may also be provided between the bearing components.
However, when the space between the bearing surfaces becomes contaminated by debris or the like, the operation of the bearing degrades. After a sufficient amount of contamination, the bearing must then either be replaced or subjected to maintenance to clear the contamination. Both replacement and maintenance are costly and require downtime.
Complex bearings are particularly susceptible to contamination from the external environment. For example, in certain applications, a bearing may need to be operable in an misaligned condition in order to accommodate the connected surrounding structure. When conventional bearing structures are moved to operate in a misaligned condition, gaps may temporarily form between the bearing components due to uneven seals or the like, exposing the internal cavity of the bearing.
Hence, a need exists for bearing assembly that can operate in a misaligned condition while minimizing exposure of the internal cavity to contaminants.